Pump



C. B. WELLS Get. 16, 1956 PUMP 2 Sheets-Sheet l Filed Nov 5, 1952 INVENTOR. CQJQS ZZ/QZZS,

C. B. WELLS Get. 16, 1956 PUMP 2 Sheets-Sheet 2 Filed Nov 5, 1952 QW, WNW @NJ MJ United States pas PUMP

Charles B. Wells, Rockford, Ill., assignor to Sundstrand Machine Tool Co., a corporation of Illinois Application November 5, 1952, Serial No. 318,844

8 Claims. (Cl. 103-5) This invention relates to a pump and to a unit for supplying atomizing air and liquid to an atomizing nozzle utilizing such pump.

It is the general object of the invention to produce a new and improved pump and unit of the type described.

A more specific object of the invention is to produce a pump provided with by-pass means for by-passing fluid moved by the pump upon the existence of excessive pump discharge pressure.

Yet another object of `the invention is to produce a pump including a compartment into which fluid to be moved by the pump is introduced and from which iluid is expelled by the pump through port forming means, with the pump being constructed and arranged so as to provide a leakage path between the compartment and the port forming means, which path is closed during normal operation of the pump and opened upon the existence of excess discharge pressure in the compartment to by-pass fluid therethrough.

Still another object of the invention is to produce a pump of the type described including a cylinder block housing a plurality of pumping pistons and a port plate provided with means forming intake and discharge ports for the pump, with the cylinder block and port plate being normally held in sealing relationship and being relatively movable so as to permit leakage of uid therebetween in the event the pump discharge pressure exceeds a predetermined amount.

fStill another object of the invention is to produce a positive displacement metering pump including a rotatable cylinder block having pumping pistons therein, and a stationary port plate having openings `forming intake and discharge ports for the pumping cylinders, together with the spring means for normally holding the cylinder block in sealing relationship against the port plate and yieldable under excess discharge pressure to permit the cylinder block to move away from the port plate whereby to bypass the iluid discharged from the cylinders into a chamber surrounding the cylinder block.

Yet another object of the invention is to produce a unit for supplying primary atomizing air to lan atomizing device together with metered quantities of liquid to be atomized thereby, with the liquid being supplied by a metering pump having separable parts normally held in sealing relationship but movable under excess discharge pressure to permit iow of liquid into a surrounding bypass chamber.

Another object of the invention is to produce a unit of the type described in the preceding paragraph including a passage connecting the pump to the nozzle and a valve controlling the passage, with the valve being normally held in closed position and adapted to be opened by primary air pressure when said pressure reaches a predetermined amount to permit ow of `liquid to the `atomizing device, together with means dening a leakage path in the pump for by-passing liquid moved by the pump during such time as the valve is closed.

Other and further objects of the invention will be 2,766,693 Patented Oct. 16, 1956 ICC readily apparent from the following description and drawings, in which:

Fig. 1 is a schematic View of the various devices incorporated in the air-liquid unit of the invention;

Fig. 2 is a longitudinal sectional view through a unit incorporating the devices of the invention;

Fig. 3 is a sectional view taken substantially along line 3 3 of Fig. 2 showing the metering pump and one side of the port plate; and

Fig. 4 is a view showing the opposite side of the port plate.

While this -invention is susceptible of embodiments in many diiferent forms, there is shown in the drawings and will herein be described in detail one speci'c embodiment, with the understanding that the present disclosure is to be considered as an exempliiication of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. rPhe scope of the invention will be pointed out in the appended claims.

Referring now to Figs. 1 and 2 of the drawings, the invention is `shown as incorporated in a unit for use with an oil burner employing a low pressure type atomizing nozzle, that is, a nozzle wherein the fuel is supplied thereto in metered quantities by a pump and is atomized by the use of primary air under pressure. The unit comprises a `casing 10 rotatably supporting a drive shaft 11. Mounted `on the drive shaft to be driven thereby is ian air blower 12 forming a source of primary atomizing air under pressure, a gear type lift pump 13 for pumping fuel from a tank together with a shaft seal 14 intermediate the blower and lift pump. Fuel delivered from the lift pump 13 is directed to `the intake side of a metering pump 15 which delivers a metered quantity of oil to the nozzle of the burner through a primary-air-.operated shut-olf valve 16. The lift pump has a purging capacity in excess of the capacity of the metering pump and such excess is used to obtain a delivery of substantially air-free oil to the metering pump and may also be used for lubrication purposes.

The primary air blower Air is supplied to the blower 12 through an intake baille 20 surrounding the drive shaft at the right-hand end (as seen in Fig. 2) of the casing and air from the baille is delivered through a passage 21 to the blower. The blower comprises a cylindrical member 23 fixed to the shaft 11 and provided with a plurality of radial slots 24 in which varies 25 are slidable. Surrounding the member 23 is an eccentric chamber 26 so proportioned as to provide between any .two vanes 25, as the member 23 is rotated, an expanding `cham-ber connected to the inlet 21 and a contracting chamber connected to sa blower exhaust passage 27. The exhaust passage 27 connects with another passage 28 leading at one end to an air pressure regulating device 29 comprising a needle valve 30 positioned in `a passage 31 and connected to the intake 2l. The needle is carried by a screw 32 and a nylon plug 33 extends into a hole through the threads of the screw to provide means for holding the screw in whatever position it may be adjusted. The taper of the needle 30 is adapted to vary the effective diameter of the passage 31 as the screw to which it is secured is adjusted longitudinally thereof so as to provide a readily available by-pass for the air discharged from the blower and thus to provide means for regulating the pressure of the primary air to be delivered to the atomizing nozzle. The other end of the passage 28 is connected to a port 24 in turn adapted to be connected to an atomizing nozzle.

The primary air pressure operated shut-0H valve The shut-01T valve 16 is constructed to control the ow of fuel to the atomizing nozzle and to be normally closed so as to prevent such flow until the primary air pressure reaches a predetermined amount. Thus the shut-olf valve 16 is normally closed on the start np of the unit and opens only after sufficient speed of the unit has been attained so as to build up primary air pressure in an amount suficient to produce proper atomization. The valve is constructed that should, at any time, the prim-ary air pressure fail, the supply of fuel to the atomizing nozzle will simultaneously be cut off. For this purpose there is provided a pilot passage 35 interconecting the passage 2S and a chamber 36 formed in the by-pass valve housing. Located within the chamber 36 is a diaphragm 37 whose edges are secured between the edge of the housing for the by-pass valve and a cover plate 3S. The diaphragm carries at its center a lock nut 39 to which is secured the stem 4G of a piston valve 41 reciprocable a cylinder 42. A spring 41a surrounds the nut 3% and has one end bearing against the cover 33 and the other end bearing against the diaphragm so as constantly to bias the piston valve to closed position. The piston 41 controls a port 43 connected to a passage 44 in turn connected to the discharge side of the metering pump l5. rhe piston valve also controls a second port 45 connected to one end of a passage 46 whose other end is connected to the atomizing nozzle. Movement of the piston valve to open position in response to the build up of primary air pressure to an amount sufficient to overcome the spring 41a establishes communication between the passages 44 and 46 to permit ow of fuel to the atomizing nozzle. A passage 47 connects with an annular groove 48 on the piston 41 and to the blower 12. Thus oil leaking along the sides of the piston 41 is directed by the annular groove and passar` 47 to the blower to provide lubrication therefor.

The shaft seal A shaft seal is provided between the blower 12 and the lift pump 13 to prevent leakage of fuel oil along the shaft. The shaft seal 14 includes a fixed part 5t) sealed in a recess 51 in the casing by an O-ring S2 as shown. Cooperating with the fixed seal lil is a rotating seal 53 which rotates with the shaft 11 and is sealed thereto by means of an @Jing 54. The rotary seal 53 is urged against the sealing face of the fixed seal by a spring 55 which presses at one end against an intermediate washer 56 and is supported at its other end in a cup-shaped member 57 press-fitted on the shaft 11.

The lift and metering pumps The lift pump 13 includes a gear S keyed to the shaft 11 and meshing with an internally toothed ring gear S9 having a diameter larger than the gear 53 to provide space for intervening crescent 60. A fixed outer ring 66a surrounds the ring gear 59 to enclose the gear pump within a recess forming a pumping chamber. An inlet 61 for the pump 13 opens at one end to the lift pump intake port 62 and at the other end to a reservoir 63 provided with a screen 64 and an inlet 65 from the fuel oil supply tank. The outlet 66a of the lift pump 13 discharges into a vertically extended recess 66 (Fig. 4) formed in one side of a port plate '76. The lift pump outlet discharges into the recess at a point spaced above the lowest portion thereof for the purposes hereafter explained. The upper portion of the recess 66 is connected to a by-pass passage 67 which, in the single pipe system shown, delivers excess oil from the lift pump to the recess S1 in which the shaft seal 14 is located. in single pipe installations, fuel delivered by the lift pump in excess of the quantity pumped by the metering pump is directed to the shaft seal to provide lubrication therefor, with oil being drained from the recess 51 by means of a passage 66 connected to the reservoir. In two pipe installations, a plug 67a closing return port 67h may be removed land a blocking plug threaded into the portion 67C of the passage to direct such excess oil through the return port to tank.

As will be evident, the primary purpose of the lift pump is to deliver fuel to the cylinders of the metering pump and is required only where the supply tank is not so located as to provide gravity feed. If the installation is such as to provide gravity feed, the lift pump may be omitted,

The other end of the passage 66 connects to a recess 69 formed in the opposite side of the port plate 79, with the recess 69 providing fan arcuate intake kidney for the metering pipe. A passageway 71 interconnects the rccesses 66 and 69 and opens into the recess 66 below the point where the outlet of the lift pump is located. Inssmuch as fuel is constantly lay-passed into passage 67 and the portion thereof delivered to the passageway 71 must flow downwardly to enter the same, such fuel as is delivered to the passageway 71 is substantially air free, the entrained air bubbles rising in the recess 66 and hence moving into the by-passing flow.

Discharge of the metering pump is through a kidney '72 and thence via a slanted passage 73 and a passage 74 through the ring 60a to the metering pump discharge passage 44.

The metering pump includes a cylinder block 75 fixed to the shaft 11 for rotation therewith but slidable axially therealong by means of the spline connection including the pin 76 fixed to the block and extending into a slot 77 formed in the shaft. The cylinder block is provided with three cylinders 73 in each of which a piston 79 is reciprocable. Each piston has a portion 79a positioned exterior-1y of the cylinder and carrying a stop Si) fixed thereto. Extending between the stops and the cylinder block and surrounding each of the piston portions 79a are compression springs S1 which serve constantly to urge the pistons 79 outwardly on their intake strokes.

A swash plate is provided for moving the pistons 79 on their discharge strokes to pump fuel to the atomizing nozzley the swash plate being fixed to the cover 82 of the reservoir and comprising a cam block 83 having a face 84 slanted with respect to the axis of the shaft and carrying a centering pin S5 which rotatably supports a dislilike spin plate 86. Sliding contact is maintained between the face 84 of the cam block and the face of the spin plate adjacent thereto to provide support for the spin plate in a direction axially of the cylinders 0f the pump. The opposite face of the spin plate is provided with a plurality of recesses S7 each adapted to receive a rounded lread portion 88 formed on the outer end of each of the pistons.

Operation In operation the shaft 11 is connected to a suitable motor, such as an electric motor, and the fuel oil passage 46 is connected to an atomizing nozzle as is the primary air port Z4. Upon initial start up of the unit the shutoff valve 16 will be in the closed position shown in Fig. 2 and will remain closed until the primary air pressure becomes suficiently high as to overcome the tension of the spring 41a which serves to maintain the piston valve 41 in closed position. When the primary air pressure reaches a predetermined amount, the diaphnagm 37 will be moved downwardly against the compression of the spring 41a to open the piston valve and to establish communication between the passages 44 and 46, thus to permit fuel pumped by the metering pump 15 to be delivered to the atomizing nozzle. During the time that the unit was operated prior to the time that the primary air pressure opens the shut-off valve, the lift pump 13 delivers oil to the intake kidney of the metering pump 1S which in turn is operated to discharge oil from the cylinders therein inasmuch as the shut-off valve 16 is, during start up, in closed position and thus no outlet is provided therethrough for the fuel delivered from the cylinders of the metering pump, the pressure within the cylinders becomes sufficiently high as to move the cylinder block bodily away from the port plate 70. Thus when the discharge pressure Within the cylinders which tends to move the cylinder block in one direction (to the left as seen in Fig. 2) becomes sufficient to overcome the g Y compression of the springs 81, the cylinder block may Shift axially by means of the spline connection 76 and 77, thus to deliver uid from within the cylinders into the reservoir 63.

When the shut-off valve finally opens upon the build up of the required amount of primary air pressure, the springs 81 serve to hold the end face of the cylinder block in sealing engagement against the port plate so as to dellver metered quantities of oil to the atomizing nozzle.

It will be clear from the foregoing that the by-pass feature of the metering pump will operate not only durlng start up or shut down but also at any time that excessive pressure is built up Within the cylinders of the pump. Thus should there occur any obstruction in the passages downstream of the metering pump to and including the atomizing oriice of the nozzle, such obstruction to fuel flow would serve to increase the pressure Within the pump cylinders. When the pressure reaches an amount sucient to overcome the springs 81 the cylinder block may separate slightly from the port plate and thus permit leakage of fluid into the surrounding reservoir. The outlet from the reservoir is so proportioned as to be able to pass all fluid discharged from the cylinders and into the surrounding reservoir when the metering pump is operating at excessive discharge pressure. Thus the by-pass feature of the metering pump provides not only a means for preventing ilow of fuel to the atomizing nozzle during times when the primary air pressure is insucient to produce proper atomization, but also opcrates as a safety feature by permitting by-pass of uid discharged under any conditions in which the discharge pressure of the metering pump exceeds a predetermined amount.

I claim:

l. A pump for fluids comprising a casing having a chamber therein, a drive shaft rotatably mounted in the casing and having a portion extending into the chamber, a cylinder block axially slidably mounted on said portion of the drive shaft and having a at end face, a plurality of axial cylinders formed in the block, with each cylinder terminating in a cylinder port in said end face and with said cylinder port having a cross-sectional area substantially equal to the cross-sectional area of its associated cylinder, a piston reciprocable in each cylinder, means for moving the pistons through intake and discharge strokes with rotation of the cylinder block, a port plate in the chamber having a at face adapted sealingly to engage the end face of the cylinder block, said port plate having an inlet port positioned to be in communication with the cylinder ports of the cylinders on the intake stroke of the pistons therein and a discharge port positioned to be in communication with the cylinder ports of the cylinders on the discharge stroke of the pistons, spring means urging the cylinder block toward the port plate sealingly to press the end face against the face of the port plate, said spring means being yieldable under excess discharge pressure to permit axial sliding movement of the cylinder block on said shaft to separate said faces to pass uid discharged from the cylinder ports into said chamber, and a by-pass outlet connected to the chamber and having a capacity suicient to drain from the chamber all fluid so passed thereinto.

2. A pump for uids comprising a casing having a chamber therein, a rotatable cylinder block in the chamber, a plurality of axial cylinders formed in the block, with each cylinder terminating in a cylinder port having a cross-sectional area substantially equal to the crosssectional area of its associated cylinder, la piston reciprocable in each cylinder, means for moving the pistons through intake and discharge strokes with rotation of the cylinder block, a port plate in the chamber having an intake port positioned to be in communication with the cylinder ports of the cylinders on the intake stroke of the pistons therein and a discharge port positioned to be in communication with the cylinder ports of the cylinders on the discharge stroke of the pistons, means urging the cylinder block into sealing engagement with the port plate and yieldable under excess discharge pressure to permit the cylinder block to separate axially from the port plate to pass fluid discharged from the cylinder ports into said chamber, and a by-pass outlet connected to the chamber and having a capacity sufficient to drain from the chamber all fluid so passed thereinto.

3. A pump for fluids comprising a casing having a chamber therein, a cylinder block in the chamber, a plurality of cylinders formed in the block, with each cylinder terminating in a cylinder port having a cross-sectional area substantially equal to the cross-sectional area of its associated cylinder, a piston reciprocable in each cylinder, means in ,the casing forming an intake port and a discharge port, means for moving the pistons through intake and discharge strokes with the cylinder ports of the cylinders being in communication with the intake pont on the intake stroke of .the pistons therein 'and in communication with the discharge .port on the .discharge stroke of the pistons, means urging the -cylinder block and the port forming means into sealing engagement and yieldable under excess discharge pressure to permit relative separating movement between Kthe cylinder block and said port forming means to pass fluid discharged from the cylinder ports into said chamber, and a iby-pass outlet connected to the chamber and having .a capacity suiicient to drain `from the charnber all fluid so passed thereinto.

4. A pump for fluids comprising a `casing having a chamber therein, a rotatable cylinder block in .the chamber, an axial cylinder formed in `the block, said cylinder terminating in a cylinder port having a cross-sectional area subsantially equal yto the cross-sectional area of the cylinder, `a piston reciprocable in the cylinder, means for moving the piston through intake and discharge strokes with rotation of `the cylinder `block, a port plate having an intake port positioned to be in communication the cylinder pont on the intake stroke of 'the piston and a discharge port positioned to be in communication with the cylinder port on the `discharge stroke `of the piston, means urging the cylinder block and port plate into sealing engagement and yieldable under excess `discharge pressure to permit relative separating movement between the cylinder block and the port plate to pass iluid discharged from the cylinder port into said chamber, and a by-pass outlet connected to the chamber and having a capacity suilicient to drain from :the chamber all iluid so passed thereinto.

5. A pump for fluids comprising a casing having a chamber therein, a drive shaft rotatably mounted in the casing and having `a portion extending into the chamlber, a cylinder block axially slidably mounted on said portion of the `drive shaft and having a at end face, a plurali-ty of axial cylinders formed in the block, a piston for each cylinder, each piston having a portion reciprocable in a cylinder and `an end portion positioned exteriorly of the cylinder, a swash plate mounted in the casing to contact the ends of the piston to move the same through discharge strokes with rotation of the cylinder block, `a compression spring encircling the end por-tion of each piston and having one end bearing against a stop on 1the piston and having its other end bearing against the cylinder block to urge the pistons to move on their intake strokes, a port plate -in fthe chamber having a flat face adapted sealingly to engage the end `face of :the cylinder block, said port pla-te having an inlet port positioned to be in communication with ythe cylinder on the intake stroke of the pistons therein and a discharge pont positioned tto be in communication with the cylinders on the discharge stroke of lthe pistons, said springs serving to urge `the cylinder block to- Ward the port plate sealingly to press the end face against the face of :the port plate and being yieldable under excess discharge pressure to permit axial sliding movement of the cylinder block on said shaft lto separate said faces to pass uid discharged from the cylinders into said chamber, and a bypass outlet connected to the chamber and having a capacity suicient tto drain from the chamber all fluid so passed thereinto.

6. A metering fuel pump comprising a casing having a chamber therein, a drive shaft rotatably mounted in the casing and having a portion extending into the chamber, a cylinder block axially slidably mounted on said portion of .the drive shaft `and having a dat end face, a plurality of axial cyl-inders formed in the block, a piston ifor each cylinder, each piston having a portion reciprocable in a cylinder and an end portion positioned exteriorly of rthe cylinder, a swash plate lixed in the casing to Contact the ends of the piston to move the same through discharge strokes with rotation of the cylinder block, a compression spring encircling `the end portion of each piston and having one end bearing against a stop on the piston and having its other end bearing against the cylinder block to urge the pistons to move on their intake strokes, a port plate in the chamber having a at face adapted sealingly to engage the end face of the cylinder block, said port plate having an inlet port positioned to be in communication with `the cylinder on the intake stroke of the pistons therein and a discharge port positioned to he in communication with the cylinders on `the discharge stroke of tthe pistons, means connecting lthe discharge port to a discharge passage, a lift pump connected to the intake port for supplying :fuel thereto, said springs serving to urge the cylinder block toward the port plate sealingly to press t-he end face against the face of the port plate and being yieldable under excess discharge pressure to permit axial sliding movement of the cylinder block on said shaft .to separate said faces to pass iluid discharged from lthe cylinders into said chamber, and a oy-pass outlet connected to the chamber and having a capacity suflicient to drain from the chamber all fluid so passed thereinto.

7. A pump for fluids comprising a casing having a chamber therein, a drive shaft rotatably mounted in the casing and having `a portion extending into Ithe chamber, a cylinder block axially slidably mounted on said portion of the drive shaft .and having a at end face, `a plurality of axial cylinders formed in the block, a piston for each cylinder, each piston having a portion reciprocable in a cylinder and an end portion positioned exteriorly of the cylinder, a cam block fixed in the casing having a face positioned at an acute `angle with respect to the axis of the drive shaft, a spin plate supported by the cam block for rotation in a plane parallel to the last mentioned face and positioned .to Contact the outer ends yof the piston to move the same through discharge strokes with rotation of the cylinder block, a compression spring encircling the end portion of each piston and having one end bearing against .a stop on :the piston and having i-ts other end 'bearing against the cylinder block to urge .the pistons to move on their intake strokes, a port plate in the chamber having a flat face adapted sealingly to engage the end face 'of the cylinder block, said port plate havin-g an inlet port positioned to be -in communication with the cylinder on the intake stroke of the pistons .therein and a discharge port positioned to be in communication with the cylinders on the discharge stroke of the pistons, said springs serving to urge the cylinder block toward .the port plate Sealingly to press the end face against the face of the pont plate and being yieldable under excess discharge pressure to permit axial sliding movement of the cylinder block on said shaft to separate said lfaces to pass uid discharged from the cylinders into said chamber, and a by-,pass outlet connected to the chamber and having a capacity sufficient yto drain from the chamber all fluid so passed Ethereinto.

8. A pumping system lcomprising a casing, a rotatinglbar-rel type piston metering pump in the casing, a ge'ar type lift lpump in the casing and having a pumping capacity in excess of the capacity of :the metering pump, a 'port plate in .the casing intermediate the pumps, said port plate having a vertically extended recess formed on one side thereof, an outlet for 'the lift pump opening into said recess at a point spaced above the lowest portion thereof, said port plate having an arcuate recess lformed on the opposite side .thereof providing an intake kidney for the metering pump, a passageway in the port plate connecting the arcuate recess with the portion of 'said vertically extended recess helow said point, and a lby-pass passage connected to the portion of said vertically extended vrecess above said point.

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